Some medical procedures are performed using a three-dimensional (3D) image of a patient. One example of a 3D image used in medical procedures is a computed tomography (CT) scan which combines multiple X-ray measurements taken from different angles to produce cross-sectional virtual “slices” of specific areas of a patient, thereby enabling a physician to see inside the patient without a need for surgery.
U.S. Patent Application 2003/0152897 to Geiger describes a method for automatic navigation during a virtual endoscopy, by navigating a viewpoint of a virtual endoscope in a lumen of a structure. The method includes determining an initial viewpoint of the virtual endoscope, and determining a longest ray from the initial viewpoint to the lumen.
U.S. Patent Application 2008/0118117 to Gauldie et al., describes a method for orienting a virtual camera for rendering a virtual endoscopy image of a lumen in a biological structure. The method includes calculating suitable paths that avoid a wall in the lumen by using ray casting to find the longest ray from a camera position to the wall.
U.S. Patent Application 2007/0052724 to Graham et al., describes a method for navigating along a biological object with a lumen represented by a three-dimensional volume data set. The method includes generating a multiple navigation segments connectable in a sequence, casting groups of rays outwards from the start point of the segment to the object wall to determine respective directions of each segment, and calculating an average ray length for each of the groups.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.
Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.